There are provided electrical connection boxes mounted at various places in the motor vehicle. The electrical connection box, which is also referred to as a fuse block, a relay box or a junction block, is composed of a box body, an electric components mounted to the box body and a cover member covering for example an upper side of the box body. Examples of the electric components may include, for relatively small ones, a relay or a fuse, and for relatively large ones, a power distribution unit. The power distribution unit itself may be referred to as the electrical connection box.
Referring to FIG. 7, there is shown a power distribution unit 1. This power distribution unit 1 distributes electric power supplied from a power source such as a battery. The power distribution unit 1 includes a circuit board 2 formed for example into a rectangular shape, a plurality of relays 3 mounted on a surface of the circuit board 2, elements such as resistors, transistors and ICs (not shown) which are also mounted on the circuit board 2, a connector block 4 arranged at one side of the circuit board 2 and a power block 5 (or a fuse block) arranged at the other side of the circuit board 2 opposite to the connector block 4.
The circuit board 2 may be, for example, a metal core substrate. The metal core substrate includes a conductive metal core (e.g., a copper core) and thus is excellent in heat dissipation and in prevention of disturbance of electromagnetic wave.
As shown in FIG. 7 and FIG. 8, the connector block 4 includes a group of terminals 6 and a group of terminals 7, each group having a plurality of terminals made of conductive metal and an insulating member 8 made of insulating resin. For the group of terminals 6 and the group of terminals 7, a board connection portion (no reference sign applied) of each terminal is connected with a distribution circuit (not shown) of the circuit board 2. The insulating member 8 is screwed to the surface of the circuit board 2.
The power block 5 includes a plurality of L-shaped plate terminals made of conductive metal, a plurality of conductive bus bars 11 having a fork-shaped terminal 10 and an insulating member 12 made of insulating resin. The L-shaped plate terminal 9 is a plate-like terminal having a mating-terminal connection portion 13, a bent portion 14 and a board connection portion 15. The L-shaped plate terminal 9 is bent at the bent portion 14 and thus formed into a L-like shape as a whole.
The mating-terminal connection portion 13 is arranged parallel to the surface of the circuit board 2. That is, the mating-terminal connection portion 13 extends in a direction parallel to the circuit board. The board connection portion 15 is arranged perpendicular to the surface of the circuit board 2. That is, the board connection portion 15 extends in a direction perpendicular to the circuit board 2.
The mating-terminal connection portion 13 is provided with a fork-shaped terminal 16. An end of the board connection portion 15 is continuous with the mating-terminal connection portion 13 via the bent portion 14 and is arranged to connect with the distribution circuit (not shown) of the circuit board 2.
The fork-shaped terminal 16 of the L-shaped plate terminal 9 and the fork-shaped terminal 10 of the bus bar 11 are arranged to connect with a blade-like fuse terminal of a fuse (not shown). Specifically, the fork-shaped terminals 16 of the L-shaped plate terminals 9 are arranged to connect with a blade-like fuse terminal located at a downstream of the fuse, while the fork-shaped terminals 10 of the bus bars 11 are arranged to connect with a blade-like fuse terminal located at an upstream of the fuse.
The plurality of fork-shaped terminals 16 of the plurality of plate terminals 9 are arranged to align in a line in a transverse direction. Furthermore, the plurality of fork-shaped terminals 10 of the bus bars 11 are also arranged to align in a line in the transverse direction. Thus, the plurality of fork-shaped terminals 16 and the plurality of fork-shaped terminals 10 are arranged in laminate, forming layers.
The plurality of L-shaped plate terminals 9 and the bus bars 11 are fixed to the insulating member 12. Then, the insulating member 12 is moved down toward the surface of the circuit board 2 and screwed to the surface of the circuit board 2. When the insulating member 12 is moved down toward the surface of the circuit board 2, ends of the board connection portions are inserted into a predetermined location on the circuit board 2.
Examples of a technology related to a power distribution unit and an electrical connection box is disclosed in Documents 1 through 3 listed below.
The plurality of L-shaped plate terminals 9 shown in FIG. 8 are fixed to the insulating member 12 by using a press fitting or by using an insert molding. In a method using the press fitting, firstly a straight plate terminal 9 with the board connection portion 15 being unfolded is inserted into the insulating member 12, as shown with a dotted line in the drawing. As the insertion proceeds, a proximal end of the mating-terminal connection portion 13 is press fitted to the insulating member 12. Then, the board connection portion 15 is bent at a right angle at the bent portion 14 to form the plate terminal 9 into a L-shape, thereby completing the formation of the L-shaped plate terminal 9 and finishing the series of process.
Since the L-shaped plate terminal 9 has the fork-shaped terminal 16 formed at the mating-terminal connection portion 13, the L-shaped plate terminal 9 needs be inserted into the insulating member 12 from a side of the L-shaped plate terminal 9 adjacent to the board connection portion 15 in order to avoid the deformation of the fork-shaped terminal 16. Consequently, if the L-shaped plate terminals 9 are preliminary formed into the L-shape before the insertion, such L-shaped plate terminals 9 cannot be inserted into the insulating member 12. Thus, the plate terminals 9 need to be straight with the board connection portion 15 unfolded before the insertion. Therefore, there is required a step of bending the board connection portion 15 after it is press fitted into the insulating member 12. There is also a problem that, it is difficult to achieve the optimum positioning of the board connection portions 15 with respect to the circuit board 2 unless the bending of the board connection portion 15 is performed accurately using a separately provided equipment or facility.
Furthermore, if the ends of the board connection portions 15 are not positioned on the circuit board 2 in an optimum manner, the board connection portions 15 cannot be inserted into a predetermined location on the circuit board 2. Such failure will adversely affect the workability of the following processes. In addition, the use of the separately provided equipment or facility causes an increase in the cost. Especially, the cost will further increase to improve the accuracy of the bending.
The difficulty in the optimum positioning of the board connection portions 15 of the L-shaped plate terminals 9 with respect to the circuit board 2 is caused by the long distance between the location on the L-shaped plate terminal 9 press-fitted to the insulating member 12 and the location on the board connection portion 15 connected with the circuit board 2. Furthermore, the difficulty in the optimum positioning of the board connection portions 15 is also caused by the location of the bent portion being arranged between the location on the L-shaped plate terminal 9 press-fitted to the insulating member 12 and the location on the board connection portion 15 connected with the circuit board 2.
Furthermore, the method using the press fit of the L-shaped plate terminals 9 has another problem that, if the L-shaped plate terminals 9 are not press fitted firmly, there is produced a looseness in the fixation of the L-shaped plate terminals 9, which may also cause the difficulty in the optimum positioning of the L-shaped plate terminals 9 with respect to the circuit board 2.
Furthermore, the method of using an insert molding of the L-shaped plate terminals 9 has a problem that it requires a separately provided facility for the insert molding and requires a complex process in the insert molding.